Question

We have a simple LOB application that:

• pulls data from EF
• serves data across the wire with WCF Data Services
• renders that data on Telerik’s RadGridView

This works really well in the default scenario as users are able to filter data by using the built-in Telerik filter control which presents all the options they want.

The problem happens when re-constructing the query sent from WCF Data Services when the ‘Contains’ operator is used:

• WCF Data Services adds a bunch of “IIF” lambda expressions which,
• EF then expands into T-SQL CASE statements

This takes a query that should look like:

SELECT TOP (25) 
[Project1].[TaskID] AS [TaskID], 
[Project1].[ProductSubmissionID] AS [ProductSubmissionID], 
...
FROM ( SELECT 
    [Extent1].[TaskID] AS [TaskID], 
    [Extent1].[ProductSubmissionID] AS [ProductSubmissionID], 
    ...
FROM     [dbo].[Task] AS [Extent1]
    LEFT OUTER JOIN [dbo].[OperationDataProduct] AS [Extent2] ON [Extent1].[ProductID] = [Extent2].[ProductID]
    LEFT OUTER JOIN [dbo].[vProductOwnership] AS [Extent3] ON [Extent1].[ProductID] = [Extent3].[ProductID]
    LEFT OUTER JOIN [dbo].[User] AS [Extent4] ON [Extent2].[ChannelManagerID] = [Extent4].[UserID]
    LEFT OUTER JOIN [dbo].[User] AS [Extent5] ON [Extent2].[ProductOwnerID] = [Extent5].[UserID]
    WHERE [Extent1].Type IN ('Content','Concept','Financial') AND [Extent1].MarketplaceName LIKE '%prod%'

Into one that looks like this:

SELECT TOP (25) 
[Project1].[TaskID] AS [TaskID], 
[Project1].[ProductSubmissionID] AS [ProductSubmissionID], 
...
FROM ( SELECT 
    [Extent1].[TaskID] AS [TaskID], 
    [Extent1].[ProductSubmissionID] AS [ProductSubmissionID], 
    ...
FROM     [dbo].[Task] AS [Extent1]
    LEFT OUTER JOIN [dbo].[OperationDataProduct] AS [Extent2] ON [Extent1].[ProductID] = [Extent2].[ProductID]
    LEFT OUTER JOIN [dbo].[vProductOwnership] AS [Extent3] ON [Extent1].[ProductID] = [Extent3].[ProductID]
    LEFT OUTER JOIN [dbo].[User] AS [Extent4] ON [Extent2].[ChannelManagerID] = [Extent4].[UserID]
    LEFT OUTER JOIN [dbo].[User] AS [Extent5] ON [Extent2].[ProductOwnerID] = [Extent5].[UserID]
    WHERE (CASE WHEN (CASE WHEN (((CASE WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END IS NULL) THEN CAST(NULL AS bit) WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%') THEN cast(1 as bit) WHEN ( NOT (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%')) THEN cast(0 as bit) END) = 1) AND ([Extent1].[SubmissionOrTaskType] IN (N'Content',N'Concept',N'Financial'))) THEN cast(1 as bit) WHEN ( NOT (((CASE WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END IS NULL) THEN CAST(NULL AS bit) WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%') THEN cast(1 as bit) WHEN ( NOT (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%')) THEN cast(0 as bit) END) = 1) AND ([Extent1].[SubmissionOrTaskType] IN (N'Content',N'Concept',N'Financial')))) THEN cast(0 as bit) END IS NULL) THEN cast(0 as bit) WHEN (((CASE WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END IS NULL) THEN CAST(NULL AS bit) WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%') THEN cast(1 as bit) WHEN ( NOT (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%')) THEN cast(0 as bit) END) = 1) AND ([Extent1].[SubmissionOrTaskType] IN (N'Content',N'Concept',N'Financial'))) THEN cast(1 as bit) WHEN ( NOT (((CASE WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END IS NULL) THEN CAST(NULL AS bit) WHEN (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%') THEN cast(1 as bit) WHEN ( NOT (CASE WHEN ([Extent1].[MarketplaceName] IS NULL) THEN CAST(NULL AS varchar(1)) ELSE LOWER([Extent1].[MarketplaceName]) END LIKE N'%prod%')) THEN cast(0 as bit) END) = 1) AND ([Extent1].[SubmissionOrTaskType] IN (N'Content',N'Concept',N'Financial')))) THEN cast(0 as bit) END) = 1
)  AS [Project1]
ORDER BY [Project1].[TaskID] ASC

My question is: has anyone bumped into this problem before and is there a low cost solution?

I can see re-writing the EF QueryProvider to be a solution, but it’s not exactly low cost.

TIA

Answer 1

We wound up writing a QueryProvider to fix this issue. It wound up being lower cost than originally expected, but still adds quiet a bit of unnecessary complexity. The IQToolkit has some decent examples of how to begin this.